A combined investigation of the molecular basis of cellular regulatory mechanisms is proposed. Included in the program are molecular geneticists, cellular physiologists, physical biochemists, and x-ray structure specialists working together in contiguous laboratories with shared facilities. The regulation and integration of DNA synthesis with other biosynthesis as well as the relation between genetic recombination and DNA synthesis. The control of genetic transcription will be investigated through studies of the direct interaction of purified components (repressors and operators) and of model systems. Protein synthesis studies will include chain termination, tRNA conformation and function, and integration with RNA synthesis. Membranes and other macromolecular assemblies will be the subject of physiological studies combined with physical studies using spin- labelling, electron imaging and optical methods. Work on more complex systems will be initiated by study of the development of the vertebrate visual system. How function is determined by macromolecular structure will be attacked through x-ray diffraction analysis combined with direct studies of the effect of conformation changes on enzymatic activity.